[A Case of BRAF Mutant Cecal Cancer Treated with Encorafenib, Binimetinib, and Cetuximab Triple Therapy].

A Japanese woman in her early 70's presented to our hospital with abdominal pain and nausea. Abdominal computed tomography showed irregular wall thickening of the ileocecal region and small intestine dilatation. Colonoscopy revealed a tumor lesion at the ileocecal valve and adenocarcinoma was detected in the biopsy specimen. Accordingly, the diagnosis was cecal cancer and bowel obstruction. Right hemicolectomy was performed as palliative surgery, and laparotomy findings revealed peritoneal dissemination. The final staging was pT4a, pN2b, pM1c, pStage Ⅳc, harboring a BRAFV600E mutation. Rapid postoperative tumor progression occurred, leading to multiple liver metastases and ascites. Encorafenib, binimetinib, and cetuximab triple therapy was started as a second line regimen. The therapy was extremely effective. CA19-9 level decreased to within normal range, and the liver tumor size was visibly diminished. After receiving treatment for 2 months in outpatient care, she had to discontinue the treatment due to carcinomatous peritonitis. Unfortunately, she died 6 months after initial diagnosis. BRAF-mutated colon cancer is associated with poor prognosis. In Japan, encorafenib, binimetinib, and cetuximab triple therapy is a new BRAF targeting regimen approved in 2020. We report this clinical course in hopes of eventually achieving better outcomes for patients with this aggressive disease.

MicroRNA-20a in extracellular vesicles derived from duodenal fluid is a possible biomarker for pancreatic ductal adenocarcinoma.

Background: Pancreatic ductal adenocarcinoma (PDAC) has a high mortality rate owing to its late diagnosis and aggression. In addition, there are relatively few minimally invasive screening methods for the early detection of PDAC, making the identification of biomarkers for this disease a critical priority. Recent studies have reported that microRNAs in extracellular vesicles (EV-miRs) from bodily fluids can be useful for the diagnosis of PDACs. Given this, we designed this study to evaluate the utility of cancer EVs extracted from duodenal fluid (DF) and their resident EV-miRs as potential biomarkers for the detection of PDAC. Methods: EV-miRs were evaluated and identified in the supernatants of various pancreatic cancer cell lines (Panc-1, SUIT2, and MIAPaca2), human pancreatic duct epithelial cells, and the DF from patients with PDAC and healthy controls. EVs were extracted using ultracentrifugation and the relative expression of EV-miR-20a was quantified. Results: We collected a total of 34 DF samples (27 PDAC patients and seven controls) for evaluation and our data suggest that the relative expression levels of EV-miR-20a were significantly higher in patients with PDAC than in controls (p = 0.0025). In addition, EV-miR-20a expression could discriminate PDAC from control patients regardless of the location of the tumor with an area under the curve values of 0.88 and 0.88, respectively. Conclusions: We confirmed the presence of EVs in the DF and suggest that the expression of EV-miR-20a in these samples may act as a potential diagnostic biomarker for PDAC.

The Detection and Negative Reversion of Circulating Tumor Cells as Prognostic Biomarkers for Metastatic Castration-Resistant Prostate Cancer with Bone Metastases Treated by Enzalutamide.

Enzalutamide is a second-generation androgen receptor inhibitor that increases overall survival (OS) rates in patients with metastatic castration-resistant prostate cancer (mCRPC). This study evaluates the efficacy of circulating tumor cell (CTC) status as a prognostic biomarker following enzalutamide administration. A retrospective subgroup analysis and prognostic survey were conducted on 43 patients with mCRPC and bone metastases treated in Juntendo University-affiliated hospitals from 2015 to 2022. Patients were treated with 160 mg enzalutamide daily. CTC analyses on blood samples were performed regularly before and every three months after treatment. The relationship between the patients' clinical factors and the OS rate was analyzed using the log-rank test; the median OS was 37 months. Patients with no detected CTCs at baseline showed significantly longer OS than those with detectable CTCs at baseline. Furthermore, patients demonstrating negative reversion of CTCs during enzalutamide treatment had significantly longer OS than patients with CTC-positivity. Two biomarkers-higher hemoglobin at baseline and achieving negative reversion of CTCs-were significantly associated with prolonged OS. This study suggests that patients achieving CTC-negative reversion during treatment for mCRPC with bone metastases exhibit improved long-term OS. Chronological measurement of CTC status might be clinically useful in the treatment of mCRPC.

Preoperative frailty as a predictive factor for postoperative complications in patients with pancreatic cancer.

Frailty is considered one of the most important indicators of a patient's general condition. However, only a few studies have investigated the association between preoperative frailty and postoperative complications in pancreatic cancer. Therefore, this study aimed to examine this association in patients with pancreatic cancer. We retrospectively reviewed 52 consecutive patients who underwent pancreatectomy for pancreatic cancer between July 2019 and March 2021. Patients were classified into two groups according to the presence of postoperative complications. Their characteristics and clinical parameters, including physical function, were analyzed. Patients with postoperative complications had a higher prevalence of frailty (58.8% vs 14.3%, p = 0.003) and a shorter 6-min walk distance (380 m vs 436 m, p = 0.020) than those without postoperative complications. Logistic regression analysis identified preoperative frailty as the only independent risk factor for complications after pancreatectomy (p = 0.002). Preoperative frailty is associated with postoperative complications of pancreatectomy. Since preoperative frailty can be easily evaluated, it is a useful predictor of postoperative complications after pancreatectomy.

Minimally invasive distal pancreatectomy for pancreatic cancer: cranial-to-caudal approach with identification of Gerota's fascia (with video).

BACKGROUND: Although radical antegrade modular pancreatosplenectomy for pancreatic ductal adenocarcinoma (PDAC) has become the gold standard procedure in open distal pancreatectomy, there has been no gold standardized procedure for PDAC in minimally invasive distal pancreatectomy (MIDP). In this study, we analyzed our novel cranial-to-caudal approach (CC approach) for patients undergoing MIDP and provide a video clip illustrating the details of the CC approach. METHODS: Ninety-four patients who underwent MIDP with splenectomy between 2016 and 2021 were included in this study. The CC approach was performed in 23 (24.5%) of the 94 patients. The concept of the CC approach is easy identification of Gerota's fascia from the cranial side of the pancreas and secure tumor removal (R0 resection) wrapped by Gerota's fascia. The short- and long-term outcomes were compared between the CC and non-CC approaches. RESULTS: The median operation time and blood loss were similar between the two groups. The ratios of grade ≥ B postoperative pancreatic fistula and Clavien-Dindo grade ≥ III complications were also comparable. All patients in the CC approach group achieved R0 resection, and the R0 ratio was similar in the two groups (p = 0.345). The 2-year survival rate in CC and non-CC approach groups was 87.5% and 83.6%, respectively (p = 0.903). CONCLUSIONS: The details of the CC approach for MIDP were demonstrated based on an anatomical point of view. This approach has the potential to become a standardized approach for left-sided PDAC.

Repeated robotic pancreatectomy for recurrent pancreatic metastasis of mesenchymal chondrosarcoma: A case report.

Mesenchymal chondrosarcoma is a rare subset of sarcomas accounting for 3%-10% of all cases of chondrosarcomas. Radical resection is the only curative strategy, even in patients with metastatic tumors. However, data regarding treatment strategies remain limited owing to the small number of cases. Herein, we report a patient who underwent repeated robotic pancreatectomy for recurrent pancreatic metastasis originating from extraskeletal mesenchymal chondrosarcoma of the pelvis. First, robotic pancreaticoduodenectomy with a reconstruction of pancreaticogastrostomy was performed for synchronous pancreatic metastasis 5 months after the primary resection of mesenchymal chondrosarcoma. Ten months after robotic pancreaticoduodenectomy, tumor recurrence was observed at the tail end of the pancreas, which was removed by reperforming robotic distal pancreatectomy. Given the precise tissue manipulation that can be achieved with robotic articulated forceps, the peripheral splenic artery and pancreas were easily isolated and divided in close proximity to the tumor. The central part of the pancreas was preserved. Robotic surgery allowed safe and effective resection of the reconstructed remnant pancreas. The patient survived for 28 months after primary tumor resection. Repeated pancreatectomy with minimally invasive techniques is a feasible and curative treatment for metastatic mesenchymal chondrosarcoma.

Prognostic Impact of Preoperative Osteosarcopenia for Patients with Pancreatic Ductal Adenocarcinoma After Curative Resection.

BACKGROUNDS: The clinical significance of preoperative osteosarcopenia in pancreatic ductal adenocarcinoma (PDAC) has not been fully studied. The purpose of this study was to evaluate the role of preoperative osteosarcopenia in predicting the survival of patients with PDAC. METHODS: We retrospectively analyzed 265 patients who underwent curative surgical resection for PDAC between 2012 and 2018 in two Japanese institutes. The skeletal muscle index at the L3 vertebrae and the bone mineral density at the Th11 vertebra were calculated for the evaluation of osteosarcopenia before surgery. The relationship between perioperative osteosarcopenia and clinicopathological factors and prognosis was analyzed. RESULTS: The median overall survival (OS) and disease-free survival (DFS) of patients with osteosarcopenia were significantly shorter than those of patients without osteosarcopenia (OS: 23 and 48 months, respectively, P < 0.001; DFS: 13.4 and 21.2 months, respectively, P = 0.004). On multivariate analysis, osteosarcopenia was found to be an independent factor associated with OS (hazard ratio [HR] 1.98; 95% confidence interval [CI] 1.40-2.80; P < 0.001) and DFS (HR 1.53; 95% CI 1.11-2.10; P = 0.009). CONCLUSIONS: Preoperative osteosarcopenia may be a useful prognostic factor in patients with PDAC who undergo surgical resection. Further studies are needed to assess whether perioperative, nutritional interventions and rehabilitation contribute to improving the prognosis of these patients.

A left-sided approach for wide mobilization of the pancreas with complete dissection of the Treitz ligament (with video).

BACKGROUND: In recent years, the number of minimally invasive pancreatoduodenectomy (MIPD) has been increasing; however, the procedure has not been widely accepted due to its complexity and difficulty. We have developed a technique to mobilize the pancreas head using a left-sided approach with a focus on the complete dissection of the Treitz ligament. METHODS: This technique focuses on the secure mobilization of the pancreas head using a left-sided approach. First, the transverse mesocolon is flipped upward and the anterior side of the mesojejunum is excised to expose the first jejunal artery (1st JA) from the distal side to its origin. During the procedure, the left sides of the SMA and Treitz ligament are exposed. The Treitz ligament is retracted to the left side and dissected anteriorly. Thereafter, the jejunum is flipped to the right side and the retroperitoneum around the origin of the jejunum and duodenum is dissected to identify the inferior vena cava (IVC). The rest of the Treitz ligament is dissected posteriorly and complete resection of the Treitz ligament releases the limitation of duodenal immobility. Thereafter, dissection proceeds along the anterior wall of the IVC, and mobilization of the pancreas head is completed from the left side. RESULTS: A total of 75 consecutive patients underwent MIPD from April 2016 to July 2022. The median operation times of laparoscopic and robotic procedures were 528 min (356-757 min) and 739 min (492-998 min), respectively. The volume of blood loss during laparoscopic and robotic procedures was 415 g (60-4360 g) and 211 g (17-1950 g), respectively. There was no mortality in any of the cases. CONCLUSION: Mobilization of the pancreas head and left-sided approach using a caudal view will be a safe and useful technique for MIPD.

Bone scan index (BSI) scoring by using bone scintigraphy and circulating tumor cells (CTCs): predictive factors for enzalutamide effectiveness in patients with castration-resistant prostate cancer and bone metastases.

Reports of Bone Scan Index (BSI) calculations as imaging biomarkers to predict survival in patients with metastatic castration-resistant prostate cancer (mCRPC) have been mainly from retrospective studies. To evaluate the effectiveness of enzalutamide (ENZ) in Japanese patients with mCRPC and bone metastases using BSI (bone scintigraphy) and circulating tumor cell (CTC) analysis. Prospective, single-arm study at Juntendo University affiliated hospitals, Japan. Patients were administered 160 mg ENZ daily, with 3 monthly assessments: BSI, prostate specific antigen (PSA), CTC and androgen receptor splicing variant-7 (AR-V7) status. Primary endpoint: BSI-decreasing rate after ENZ treatment. Secondary endpoints: PSA-decreasing rate and progression free survival (PFS). Statistical analyses included the Wilcoxon t-test, Cox proportional hazard regression analysis, and log-rank test. Median observation period: 17.9 months, and median PFS: 13.8 (2.0-43.9) months (n = 90 patients). A decrease in BSI compared to baseline as best BSI change on ENZ treatment was evident in 69% patients at the end of the observation period (29% patients showed a complete response, BSI 0.00). At 3 months 67% patients showed a ≥ 50% PSA reduction, and 70% after ENZ treatment. PSA decline (3 months) significantly associated with a prolonged median PFS: 18.0 (estimated) versus 6.4 months (HR 2.977 [95% CI 1.53-5.78], p = 0.001). Best BSI decline response significantly associated with a prolonged PFS: 18.1(estimated) versus 7.8 months (HR 2.045 [95% CI: 1.07-3.90], p = 0.029). CTC negative status (n = 20) significantly associated with a prolonged PFS: 13.4 [estimated] vs 8.6 months (HR 2.366, 95% CI 0.97-5.71, p = 0.041). CTC positive/AR-V7 positive status significantly associated with a shorter PFS: 5.9 months (HR 8.56, 95% CI 2.40-30.43, p = 0.0087). -reduction (3 months) and BSI-reduction (on ENZ treatment) were significant response biomarkers, and a negative CTC status was a predictive factor for ENZ efficacy in patients with mCRPC.

Clinical Implications of FDG-PET in Pancreatic Ductal Adenocarcinoma Patients Treated with Neoadjuvant Therapy.

PURPOSE: To evaluate the clinical significance of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in patients with pancreatic ductal adenocarcinoma who underwent neoadjuvant therapy. METHODS: Among 285 consecutive patients who underwent pancreatic resection for pancreatic ductal adenocarcinoma between 2015 and 2021, 86 who underwent preoperative 18F-fluorodeoxyglucose positron emission tomography/computed tomography after completion of neoadjuvant treatment were reviewed. Among preoperative factors, including post-treatment maximum standardized uptake value, predictors of early recurrence and poor prognosis were identified using multivariate analysis for decision making in surgery. RESULTS: Nineteen (22%) patients with pancreatic ductal adenocarcinoma demonstrated high maximum standardized uptake (≥ 4.5). High post-treatment maximum standardized uptake (≥ 4.5) predicted early recurrence within 6 months after surgery and correlated with shorter recurrence-free survival. Elevated post-treatment CA19-9 level (> 37 U/ml) and maximum standardized uptake ≥ 4.5 were independent prognostic factors. Post-treatment, a high maximum standardized uptake value indicated a poorer prognosis than a low maximum standardized uptake value in both patients with elevated CA19-9 and normal CA19-9 levels. The median overall survival in patients with elevated post-treatment CA19-9 and high maximum standardized uptake was only 17 months; 67% experienced early recurrence. Dynamic changes in maximum standardized uptake during neoadjuvant therapy were correlated with pathological response to neoadjuvant therapy, but not with radiological response or change in CA19-9 level. CONCLUSIONS: Post-treatment assessment using maximum standardized uptake value is useful for stratifying patients with pancreatic ductal adenocarcinoma who will benefit from surgery. Instead of subsequent curative resection, additional neoadjuvant therapy should be considered in patients with a persistently high maximum standardized uptake value.

Kidney Transplantation for a Patient With Protein C Deficiency Using Activated Protein C Concentrate: A Case Report.

BACKGROUND: Thrombophilia causes thrombosis after kidney transplantation (KT). Protein C deficiency is a rare form of hereditary thrombophilia. To our knowledge, there are few reports on KT for patients with protein C deficiency, and there are no reports of KT in patients with protein C deficiency administered with activated protein C concentrate. METHOD: Here we reported the case of a patient with protein C deficiency who underwent KT without the occurrence of any fresh thrombosis after administration of an activated protein C concentrate. The patients was a 49-year-old woman diagnosed with immunoglobulin A nephropathy at 20 years of age. During pregnancy, she experienced deep vein thrombosis of the lower extremities and pulmonary embolism for which she was started on warfarin. After a thorough examination, the patient was diagnosed with protein C deficiency. The patient had end-stage kidney disease and received a preemptive living donor kidney transplant from her mother. RESULTS: To prevent thrombosis, we switched from oral warfarin to continuous heparin 7 days before surgery. Heparin was discontinued 6 hours before surgery, and continuous activated protein C concentrate was administered 12 hours before surgery. Heparin administration was resumed 6 hours after the surgery. Warfarin administration was restarted 3 days after the surgery, and heparin was discontinued 11 days post-surgery. The surgery was performed without complications. After the KT, the patient's renal function steadily improved, and no fresh thrombosis were observed. CONCLUSIONS: Thrombosis can cause graft loss and pulmonary embolism, thus appropriate administration of activated protein C concentrate may help prevent thrombosis.

Efficacy of cabazitaxel and androgen splicing variant-7 status in circulating tumor cells in Asian patients with metastatic castration-resistant prostate cancer.

Androgen receptor splice variant-7 (AR-V7) expression in circulating tumor cells (CTCs) in metastatic castration-resistant prostate cancer (mCRPC) is associated with abiraterone and enzalutamide resistance. We determine whether cabazitaxel (CBZ) is equally effective in AR-V7-positive and -negative CRPC and whether AR-V7-positive patients retain CBZ sensitivity. This is the first prospective, open-label, Asian validation study of CBZ in Japanese patients with mCRPC after docetaxel (n = 48; four CBZ cycles; 2017-2020, Juntendo University Hospitals). Primary endpoint was prostate-specific antigen response rate (PSA-RR); secondary endpoints included overall survival (OS), bone scan index (BSI) PSA-RR (≥ 50% decline from baseline) for CTC-/ARV7-, CTC+ /ARV7-, and CTC +/ARV7+ groups. PSA-RR ≥ - 30% was 38% (18/48) and ≥ - 50% was 26% (12/48). BSI-change rate ≥ - 30% was 19% (9/41) and ≥ - 50% was 17% (8/41). Median OS was 13.7(12.2-18.9) months. PSA decline in early CBZ treatment associated with OS (p = 0.00173). BSI decline associated with OS (p = 0.0194). PSA-RR(≥ 50%) was 43%(6/14) in CTC-/ARV7-, 19%(5/26) in CTC+ ARV7-, and 12%(1/8) in CTC+/ARV7+ ( p > 0.05). AR-V7 in CTCs at baseline not associated with OS. AR-V7 was not associated with CBZ resistance in CTCs. Reductions in BSI and PSA in early stages of CBZ treatment may predict OS.

Gallbladder Ciliated Foregut Cyst Suspected of Malignancy Preoperatively.

BACKGROUND: Gallbladder ciliated foregut cysts (CFCs) of the lower diaphragm are extremely rare. Furthermore, they are rarely suspected of malignancy preoperatively. Case Presentation. A 50-year-old woman was referred to our hospital for further examination and treatment of a gallbladder tumor that was detected using abdominal ultrasonography (US). After a close inspection, she was diagnosed with a gallbladder tumor that was possibly malignant. Accordingly, open whole layer cholecystectomy was performed because intraoperative US revealed a tumor located on the intraperitoneal side of the gallbladder, and a rapid intraoperative pathological diagnosis identified no malignancy. A postoperative pathological examination revealed a cystic lesion with thin walls covered with ciliated epithelium, which laid on a connective tissue with smooth muscle fibers. Based on the above results, the final pathological diagnosis was CFC of the gallbladder without malignancy. CONCLUSIONS: Cases of gallbladder CFC can be considered as cysts requiring treatment owing to CFCs' potential for malignant transformation and high-frequency symptoms.

Correction to: Intramural metastasis to the appendix from ascending colon cancer: a case report.

In the original publication of this article [1], an author's name should be changed from Shin Takasue to Shin Takesue.

Intramural metastasis to the appendix from ascending colon cancer: a case report.

BACKGROUND: Intramural metastasis is rare in colorectal cancer, especially metastasis of ascending colon cancer to the appendix. CASE PRESENTATION: A 64-year-old man was admitted to our hospital for surgery for ascending colon cancer detected by medical examination. Colonoscopy identified a type-2 tumor in the ascending colon, which was diagnosed as adenocarcinoma. Abdominal computed tomography revealed focal thickening of the ascending colon and middle of the appendix and swelling of the lymph nodes around the ileocolic artery. The patient underwent laparoscopic right hemi-colectomy with D3 lymph node dissection. Histopathological findings revealed that the ascending colon cancer was moderately differentiated adenocarcinoma with lymphatic and vascular invasion (stage IIIB; pT3N2M0). Additionally, moderately differentiated adenocarcinoma was observed mainly in the submucosa and muscularis propria of the appendix, which was approximately 10 cm proximal to the ascending colon cancer. These findings indicated intramural metastasis to the appendix from the ascending colon cancer. The patient experienced recurrence with lung metastasis 2.5 years after the first surgery. CONCLUSIONS: Intramural metastasis of ascending colon cancer to the appendix is extremely rare. Because the risk of recurrence and the prognosis for intramural metastasis has not been clarified, careful follow-up is recommended.

Endoscopic Transpapillary Pancreatic Duct Stent Placement for Symptomatic Peripancreatic Fluid Collection Caused by Clinically Relevant Postoperative Pancreatic Fistula After Distal Pancreatectomy.

This study aimed to evaluate the safety and efficacy of endoscopic transpapillary pancreatic duct stent placement (ETPS) for symptomatic peripancreatic fluid collection caused by postoperative pancreatic fistula (POPF) after distal pancreatectomy (DP). ETPS was also compared with percutaneous drainage (PTD). Retrospectively 38 patients were studied who developed clinically relevant POPF. Of 38 patients, 4 underwent PTD and 11 underwent ETPS. Technical and clinical success rates of ETPS (100% and 91%, respectively) were comparable with PTD (100% and 75%, respectively). The tip of a pancreatic stent was placed over the pancreatic stump in 4 patients and draining of pus through the pancreatic stent was observed. The hospital stay after DP and the interval from intervention to discharge were significantly shorter in the ETPS group than in the PTD group. ETPS is safe and successful for managing peripancreatic fluid collection caused by POPF after DP and should be considered as a therapeutic option.

Pancreatic Juice Exosomal MicroRNAs as Biomarkers for Detection of Pancreatic Ductal Adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a lethal neoplasm because of difficulties in early detection. Several studies have recently suggested that exosomes may have potential as novel biomarkers. This study aimed to isolate exosomes from pancreatic juice and to investigate whether exosomal microRNAs (ex-miRs) could be used as biomarkers for PDAC. METHODS: Pancreatic juice was collected from patients with PDAC and chronic pancreatitis (CP) by endoscopic retrograde pancreatography. Exosomes were extracted by ultracentrifugation. The presence of exosomes was confirmed by electron microscopy and Western blotting using anti-CD63, -CD81, and -TSG101 antibodies. Relative levels of ex-miR-21 and ex-miR-155 were quantified and compared between PDAC and CP patients. RESULTS: A total of 35 pancreatic juice samples (27 PDAC and 8 CP) were collected. Relative levels of both ex-miR-21 and ex-miR-155 were significantly higher in PDAC patients compared with CP patients (p < 0.001 and p = 0.008, respectively). By contrast, no significant difference was apparent in relative levels of miR-21 and miR-155 in whole pancreatic juice from PDAC patients compared with CP patients (p = 0.08 and p = 0.61, respectively). Ex-miR-21 and ex-miR-155 levels discriminated PDAC patients from CP patients with area under the curve values of 0.90 and 0.89, respectively. The accuracies of ex-miR-21 levels, ex-miR-155 levels, and pancreatic juice cytology were 83%, 89%, and 74%, respectively. When combining the results of ex-miR profiling with pancreatic juice cytology, the accuracy was improved to 91%. CONCLUSIONS: We successfully extracted exosomes from pancreatic juice. Ex-miRs, including ex-miR-21 and ex-miR-155, in pancreatic juice may be developed as biomarkers for PDAC.

Clinical assessment of the GNAS mutation status in patients with intraductal papillary mucinous neoplasm of the pancreas.

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is characterized by cystic dilation of the pancreatic duct, caused by mucin hypersecretion, with slow progression via the adenoma-carcinoma sequence mechanism. Mutation of GNAS at codon 201 is found exclusively in IPMNs, occurring at a rate of 41-75%. Recent advances in molecular biological techniques have demonstrated that GNAS mutation might play a role in the transformation of IPMNs after the appearance of neoplastic cells, rather than in the tumorigenesis of IPMNs. GNAS mutation is observed frequently in the intestinal subtype of IPMNs with MUC2 expression, and less frequently in IPMNs with concomitant pancreatic ductal adenocarcinoma (PDAC). Research has focused on assessing GNAS mutation status in clinical practice using various samples. In this review, we discuss the clinical application of GNAS mutation assessment to differentiate invasive IPMNs from concomitant PDAC, examine the clonality of recurrent IPMNs in the remnant pancreas using resected specimens, and differentiate pancreatic cystic lesions using cystic fluid collected by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA), duodenal fluid, and serum liquid biopsy samples.

Genetic assessment of recurrent pancreatic high-risk lesions in the remnant pancreas: Metachronous multifocal lesion or local recurrence?

BACKGROUND: It is difficult to determine whether a second high-risk lesion, including pancreatic ductal adenocarcinoma or high-grade pancreatic intraepithelial neoplasm, is a metachronous multifocal lesion or represents local recurrence after resection of the first high-risk lesion. This study attempts to clarify the characteristics of second high-risk lesions in the remnant pancreas using genetic analyses. METHODS: Clinicopathologic data were collected from 12 patients who underwent pancreatectomy for a second high-risk lesion in the remnant pancreas. We performed mutational and immunohistochemical analyses of 4 major genes-KRAS, TP53, CDKN2A, and SMAD4-associated with pancreatic ductal adenocarcinoma progression, as well as targeted next-generation sequencing. RESULTS: Mutations in the four genes in the second high-risk lesion were consistent with the first lesion in four patients but were inconsistent in the remaining eight patients, and thus we considered that the latter eight patients likely had metachronous multifocal high-risk lesions and the other four patients had local recurrence. The estimated cumulative recurrence rate after resection of the second high-risk lesion was greater in the local recurrence group compared with the metachronous multifocal group, and the estimated cumulative disease-specific survival rate was greater in the metachronous multifocal group. Targeted next-generation sequencing demonstrated that the second lesions in the metachronous multifocal high-risk lesion group showed differences in founder mutations compared with the first lesion. In the local recurrence group, the founder mutations in the second lesion were common with those in the first lesion. CONCLUSION: Genetic assessment might help discriminate metachronous multifocal high-risk lesions from local recurrence.

Clinicopathological characteristics of non-functioning cystic pancreatic neuroendocrine tumors.

BACKGROUND/OBJECTIVES: The biological features of cystic pancreatic neuroendocrine tumors (PNETs) remain unclear. The aim of this study was to clarify the clinicopathological characteristics of non-functioning PNETs (NF-PNETs) with a cystic component. METHODS: The medical records of 75 patients with NF-PNETs who had undergone resection in our institution were retrospectively reviewed. Clinicopathological factors were compared between PNETs with and without a cystic component. Expression of somatostatin 2 receptor (SSTR-2) was also analyzed. RESULTS: Cystic PNETs were diagnosed in 14 patients (19%). The proportion of men was significantly higher for cystic than solid PNETs (79% vs. 44%, P < 0.05) and cystic PNETs were significantly larger than solid PNETs (25 mm vs. 17 mm, P < 0.01). However, there were no significant differences in the prevalence of lymph node metastases (14% vs. 10%, P = 0.64), hepatic metastasis (7% vs. 3%, P = 0.54), or disease-free survival rate (both 86%, P = 0.29) between PNETs with and without a cystic component. SSTR-2 expression was more frequently observed in PNETs with a cystic component than in those without (100% vs. 70%, P < 0.01). CONCLUSIONS: Although cystic PNETs were larger upon diagnosis than solid PNETs in this study, prognosis after surgical resection did not differ significantly between these types of PNET. Somatostatin receptor scintigraphy and somatostatin analogues may be more useful for diagnosing and treating cystic PNETs, respectively.